Philadelphia’s three-run 10th came after the teams played to a 1-1 tie after nine.
Aaron Rowand had a run and four hits. Chase Utley had two runs and three hits, and drove in the first run with a solo homer in the top of the first, as the Phillies stayed within two games of the first place New York Mets in the NL East with their eighth win in 10 games.
The winner was Brett Myers (5-7).
Clay Condrey recorded his second save this season.
Washington’s only run scored on Utley’s sixth inning throwing error. Ryan Church and Ronny Belliard had two hits apiece for the Nationals, who have dropped three in a row.
The losing pitcher was Chris Schroder (2-3).